/**
 * Worker for RTSemEventWaitEx and RTSemEventWaitExDebug.
 *
 * @returns VBox status code.
 * @param   pThis           The event semaphore.
 * @param   fFlags          See RTSemEventWaitEx.
 * @param   uTimeout        See RTSemEventWaitEx.
 * @param   pSrcPos         The source code position of the wait.
 */
static int rtR0SemEventLnxWait(PRTSEMEVENTINTERNAL pThis, uint32_t fFlags, uint64_t uTimeout,
                               PCRTLOCKVALSRCPOS pSrcPos)
{
    int rc;

    /*
     * Validate the input.
     */
    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
    AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
    rtR0SemEventLnxRetain(pThis);

    /*
     * Try grab the event without setting up the wait.
     */
    if (   1 /** @todo check if there are someone waiting already - waitqueue_active, but then what do we do below? */
        && ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
        rc = VINF_SUCCESS;
    else
    {
        /*
         * We have to wait.
         */
        RTR0SEMLNXWAIT Wait;
        rc = rtR0SemLnxWaitInit(&Wait, fFlags, uTimeout, &pThis->Head);
        if (RT_SUCCESS(rc))
        {
            IPRT_DEBUG_SEMS_STATE(pThis, 'E');
            for (;;)
            {
                /* The destruction test. */
                if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
                    rc = VERR_SEM_DESTROYED;
                else
                {
                    rtR0SemLnxWaitPrepare(&Wait);

                    /* Check the exit conditions. */
                    if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
                        rc = VERR_SEM_DESTROYED;
                    else if (ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
                        rc = VINF_SUCCESS;
                    else if (rtR0SemLnxWaitHasTimedOut(&Wait))
                        rc = VERR_TIMEOUT;
                    else if (rtR0SemLnxWaitWasInterrupted(&Wait))
                        rc = VERR_INTERRUPTED;
                    else
                    {
                        /* Do the wait and then recheck the conditions. */
                        rtR0SemLnxWaitDoIt(&Wait);
                        continue;
                    }
                }
                break;
            }

            rtR0SemLnxWaitDelete(&Wait);
            IPRT_DEBUG_SEMS_STATE_RC(pThis, 'E', rc);
        }
    }

    rtR0SemEventLnxRelease(pThis);
    return rc;
}
/**
 * Worker for RTSemEventMultiWaitEx and RTSemEventMultiWaitExDebug.
 *
 * @returns VBox status code.
 * @param   pThis           The event semaphore.
 * @param   fFlags          See RTSemEventMultiWaitEx.
 * @param   uTimeout        See RTSemEventMultiWaitEx.
 * @param   pSrcPos         The source code position of the wait.
 */
static int rtR0SemEventMultiLnxWait(PRTSEMEVENTMULTIINTERNAL pThis, uint32_t fFlags, uint64_t uTimeout,
                                    PCRTLOCKVALSRCPOS pSrcPos)
{
    uint32_t    fOrgStateAndGen;
    int         rc;

    /*
     * Validate the input.
     */
    AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
    AssertMsgReturn(pThis->u32Magic == RTSEMEVENTMULTI_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
    AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
    rtR0SemEventMultiLnxRetain(pThis);

    /*
     * Is the event already signalled or do we have to wait?
     */
    fOrgStateAndGen = ASMAtomicUoReadU32(&pThis->fStateAndGen);
    if (fOrgStateAndGen & RTSEMEVENTMULTILNX_STATE_MASK)
        rc = VINF_SUCCESS;
    else
    {
        /*
         * We have to wait.
         */
        RTR0SEMLNXWAIT Wait;
        rc = rtR0SemLnxWaitInit(&Wait, fFlags, uTimeout, &pThis->Head);
        if (RT_SUCCESS(rc))
        {
            IPRT_DEBUG_SEMS_STATE(pThis, 'E');
            for (;;)
            {
                /* The destruction test. */
                if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENTMULTI_MAGIC))
                    rc = VERR_SEM_DESTROYED;
                else
                {
                    rtR0SemLnxWaitPrepare(&Wait);

                    /* Check the exit conditions. */
                    if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENTMULTI_MAGIC))
                        rc = VERR_SEM_DESTROYED;
                    else if (ASMAtomicUoReadU32(&pThis->fStateAndGen) != fOrgStateAndGen)
                        rc = VINF_SUCCESS;
                    else if (rtR0SemLnxWaitHasTimedOut(&Wait))
                        rc = VERR_TIMEOUT;
                    else if (rtR0SemLnxWaitWasInterrupted(&Wait))
                        rc = VERR_INTERRUPTED;
                    else
                    {
                        /* Do the wait and then recheck the conditions. */
                        rtR0SemLnxWaitDoIt(&Wait);
                        continue;
                    }
                }
                break;
            }

            rtR0SemLnxWaitDelete(&Wait);
            IPRT_DEBUG_SEMS_STATE_RC(pThis, 'E', rc);
        }
    }

    rtR0SemEventMultiLnxRelease(pThis);
    return rc;
}